Lubricating grease return valve

ABSTRACT

An apparatus for the relief of grease under pressure in the delivery line of grease guns and similar pressure delivery devices includes a 3-port valve in which the relief port is located between the delivery and inlet ports and includes a one way flow control valve mounted therein. The one way flow control valve is maintained in a closed position by the pressure of the grease and is activated to be opened to reduce the pressure in the valve body and allow the grease to return to the grease reservoir.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a valve for returning grease under pressurefrom the delivery line of grease guns or similar pressure deliverydevices to a reservoir.

BACKGROUND ART

There are a number of different types of grease guns used for thedisplacing of highly viscous products to a desired location at highpressures. Very often the delivery line of these units consists of aflexible hose to allow for ease of access to all greasing points. In thecase were high pressure is required to overcome a high resistance due totight tolerances inherent in bush type assemblies or blockages withinthe grease nipple, a swelling of the flexible hose occurs with theincrease in pressure. At the end of the greasing cycle the pressure inthe delivery line drops from the high pressure required for greasing toatmospheric pressure on disconnecting the grease coupler from the greasenipple. The result is that the delivery hose that absorbed extra greaseas it ballooned under the higher pressure now dispels this volume towaste as it returns to its normal size under atmospheric pressure. Thiswaste grease is also greatly compounded by the fact that there arealmost always small air pockets trapped within the grease which becomecompressed as the pressure in the hose rises during the greasing cycle.As the delivery line is released from the grease nipple the air pocketsincrease volumetrically as they expand to atmospheric pressuredisplacing still more grease out the end of the delivery line resultingin additional waste grease. This waste increases grease consumption,becomes a fire hazard when left on machinery and becomes anenvironmental hazard when dropped onto the ground and allowed to enterwater systems. By being able to relieve the grease under pressure in thedelivery line on completion of the greasing cycle back into apredetermined reservoir a significant reduction in waste grease can beachieved, thereby creating a cost effective and environmentally friendlygreasing system.

Another common feature in greasing systems is the use of a coupler knownin the art as the Zerk grease coupler. This coupler allows for a highpressure connection between the grease delivery line and the greasingpoint (the grease nipple). A common feature of the Zerk grease coupleris that it is designed such that the pressure generated within thedelivery line assists with the gripping of the grease coupler to thegrease nipple. Therefore the higher the pressure generated within thedelivery line the higher the force with which the coupler grips thegrease nipple. In the case where the greasing cycle is complete andthere remains a pressure within the delivery line the operator will needto vigorously oscillate the coupler relative to the grease nipple tocause a by-pass of grease and allow for a pressure drop in the deliveryline and in turn enable the coupler to release the grease nipple. Inthis process the coupler and the nipple are inclined to become damagedin time as well as generating waste grease every time the pressure isrelieved at the grease nipple in such a manner. With the inclusion of apressure relief valve, on completion of the greasing cycle the pressurewithin the delivery line may be relieved either manually orautomatically back into the grease reservoir and the coupler can beremoved with ease. By using this methodology the life of both thecoupler and nipples will be extended as well as a reduction in wastegrease will be achieve. These positive outcomes will be directlyresponsible for a reduction in greasing costs.

Trials have shown that due to the benefits of this invention dramaticreductions in the waste of grease can be achieved. Furthermore thelongevity of both grease couplers and grease nipples are increasedsignificantly. Cumulatively these savings are very significant asmillions upon millions of greasing cycles are completed globally everyday.

DISCLOSURE OF THE INVENTION

According to the invention there is provided an apparatus for the reliefof grease under pressure within the delivery line of a grease gun orsimilar displacement mechanism which comprises a three-port valve bodylocated prior to the delivery line, the valve body including a pressureinlet port, a delivery port to which the delivery line is attached and apressure relief port, which discharges to a reservoir, located betweenthem; the pressure relief port including a one way flow control valvemountable therein and activation means for the one way flow controlvalve; wherein the one way flow control valve is maintained in a closedposition by the pressure of grease within the three-port valve body andis activated to be opened when required thereby allowing the deliveryline pressure to reduce to atmospheric pressure as grease is releasedback into the grease reservoir.

All three ports are interlinked via three elongate passages. The reliefport is located between the delivery port and pressure inlet port. Aone-way check valve in the pressure inlet port allows for the viscoussubstance to only flow in the delivery direction and inhibits any flowin the opposite direction. The one way flow control valve is locatedwithin the pressure relief port which remains completely sealed with anypressure generated beyond the pressure inlet check valve. In other wordsit is a positive seal. The delivery port allows for some form ofdelivery line to be attached to the body of the apparatus therebyallowing the viscous substance to be delivered to its desired location.

In the preferred form of the invention, the one way flow control valvecomprises a valve ball and a valve seat, the pressure of the greasewithin the valve body exerts pressure on the valve ball and maintains itin sealing contact with the valve seat. The valve seat is preferablymounted in the valve port by screwing it in, the two beingcorrespondingly screw-threaded for this purpose.

Also in the preferred form of the invention, the valve seat comprises abody having an elongated internal passage of diameter smaller than thatof the valve ball. An activation rod is provided which comprises astepped shaft with the smaller end thereof slidably located within theinternal passage of the valve seat. This smaller diameter end isdimensioned to permit passage of grease there past into the greasereservoir. The opposite end with a larger diameter (for practicalpurposes) is positioned to allow for a mechanical driver to engage theshaft thereby advancing the valve ball off the valve seat.

The activation rod is loosely located within the valve seat passage andis supported by a retaining formation which retains the activation rodwithin the valve seat passage and maintains the rods alignment with themechanical driver element. The mechanical driver element is preferably aformation on some form of lever or treadle which has the ability torotate and thereby allowing the driver element to engage the activationrod and thereby opening the one way flow control valve.

To operate the invention the activation rod needs to be displaced inorder for it to advance the ball of the one way flow control valve offthe valve seat. This allows the free flow of grease through the elongatepassage of the one way flow control valve seat, past the loosely fittingactivating rod, back into the grease reservoir.

In the first instance this may be achieved manually. It follows that inany manual grease gun the activating handle or treadle will be outsideof the grease reservoir while the pumping mechanism will be within thereservoir of grease. The external movement of the treadle or handle istransferred to within the grease reservoir where a driving element isfixed in an appropriate position relative to the activation rod. Thus byraising the handle or treadle at the end of the greasing cycle whilethere is still residual pressure within the delivery line the movementis carried through to the activation rod and in turn advances the reliefvalve ball off the relief valve seat thereby allowing grease underpressure within the delivery line to return to the reservoir. Othermechanical means of opening this valve such as cams and levers can bedevised.

In the second instance the one way flow control valve may be openedautomatically. As in the example above at the end of a greasing cyclewith the return springs having pulled the pump (and its linkage) to itsextreme position on the inlet stroke, the activating rod can be lengthensuch that the one way flow control valve ball is already advanced offthe valve seat in this position. It therefore follows that the pressurein the delivery line is automatically relieved at the end of each cycle.

In the third instance the activating rod may be advanced to open therelief valve by an external power source triggered by the operator. Thiscould take the form of electrical, hydraulic or pneumatic means.

It must be noted that the one way flow control valve is not a pressuresensitive valve but operator controlled irrespective of the deliveryline pressure. Once the activation force has been released from theactivation rod the one way flow control valve ball will remain in theopen position until such time that further pressure is introduced viathe pressure inlet port. Due to the viscous nature of the material beingpumped and the limited tolerances between the port and the ball, the oneway flow control valve ball is carried to the valve seat in as soon aspumping starts, thereby preventing grease from returning to thereservoir as the pressure increases.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the invention is described below withreference to the accompanying drawings in which:

FIG. 1: shows a cross-sectional view of the greasing systemincorporating the grease pump, reservoir, one way flow control valve,delivery line, grease coupler and grease nipple. The manual or automaticcontrol lever/treadle is also shown with arrows depicting rotation ofthe controlling arms and the movement of the activation rod.

FIG. 2: shows the one way flow control valve assembly including inlet,outlet and pressure relief porting. The grease gun's delivery checkvalve and one way flow control valve are both shown in the fully closedposition. Arrows depict the movement required by the activation rod toallow for the one way flow control valve ball to be moved from its seatallowing grease under pressure to be relieved from the system back tothe reservoir.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, the apparatus for relieving grease underpressure in the delivery line is detailed. It must be noted that inorder to clearly depict the application and relevance of the one wayflow control valve a number of extra components are included in thefigures which do not necessarily relate directly to the patent. Forexample, the bearing/bush, grease nipple and grease coupler depicted inFIG. 1.

Referring to FIGS. 1 & 2, when the operator initiates the first deliverystroke on the grease pump, 2, the grease passes at pressure into theapparatus 12 through the inlet pressure port, 14. The delivery checkvalve, 18, allows only one directional flow of grease from the inletport into the apparatus, 12. The pressure generated within the apparatusensures that the one way flow control valve ball, 17, forms a positiveseal against the valve seat, 13. Due to the highly viscous nature ofgrease no retaining spring is required for the valve ball 17. Theslightest flow of grease carries the valve ball 17 towards the valveseat 13 and forms an efficient seal in an instant.

On further stroking of the grease pump whether it is by manual ormechanical means the grease has no option but to pass through thedelivery port, 16, and in turn down the delivery line, 8 as the one wayflow control valve ball 17 is firmly seated in the valve seat 13,closing the valve.

When the grease coupler, 7 and grease nipple, 6 are engaged and whilethe grease pump is been stroked the grease travels through to thebearing/bush, 5, which requires the grease. In the instance where thereare tight tolerances within the bearing/bush or there is a blockage inthe grease nipple a substantial pressure can remain within the deliveryline, 8. Without allowing this pressure to dissipate (and due to thedesign of the Zerk grease coupler) it becomes very difficult to part thegrease coupler and the grease nipple as the higher the pressure in thedelivery line the higher the force with which the grease coupler gripsthe grease nipple. In such a case, when the grease coupler is forced offthe nipple grease flows to waste from the end of the delivery line (asthe ballooned hose returns to size and any air pockets within the greaseincrease in volume and force further grease out the end of the deliveryline). Removing the grease coupler while under pressure has a distinctlynegative effect on its service life and there is a high probability thatthe either the grease coupler or grease nipple will, in time, becomedamaged.

To avert this scenario the operator is required to activate theactivation rod, 9, via the manual or automatic lever/treadle, 3. Thelever includes a mechanical driver 10 which engages the top of theactivation rod 9 and advances it. The activation rod displaces the oneway flow control valve ball, 17, thereby breaking the positive sealbetween the ball 17 and the valve seat, 13. The pressurized greasewithin the apparatus and the delivery line is now relieved past therelief port check valve and activation rod back into the greasereservoir, 1. The diameter of the activation rod which protrudes intothe elongate passage within the valve seat, 13, needs to be smaller thanthe diameter of the elongate passage to a degree that allows forsufficient grease to bypass the rod on operation. The one way flowcontrol valve will then remain open.

With the initiation of a new greasing cycle the initial pressuregenerated within the apparatus carries the one way flow control valveball, 17, and the activation rod, 9, in unison in the upward directionuntil a positive seal is generated by the valve ball, 17, and the valveseat, 13.

1-12. (canceled)
 13. An apparatus for the return of grease underpressure from within the delivery line of a grease gun or similardisplacement mechanism to the grease gun reservoir, the apparatuscomprising a three-port valve body located prior to the delivery line,in which the valve body includes a pressure inlet port, a delivery portto which the delivery line is attached and a pressure relief portlocated between them, the pressure relief port including a one way flowcontrol valve mountable therein and an activation means for the one wayflow control valve; the one way flow control valve being maintained in aclosed position by the pressure of grease within the three-port valvebody and is activated to be opened when required; characterized in thatthe relief port is linked to the grease gun reservoir by an elongatedpassage to permit grease under pressure to be returned to the grease gunreservoir on activation of the one way flow control valve, therebyallowing the delivery line pressure to reduce to atmospheric pressure.14. The apparatus for the return of grease under pressure according toclaim 13, wherein the one way flow control valve is located within thepressure relief port which remains completely sealed with any pressuregenerated beyond the delivery check valve, the seal between the one wayflow control valve and the relief port being a positive seal.
 15. Theapparatus for the return of grease under pressure according to claim 13,wherein the one way flow control valve comprises a valve ball and avalve seat, the pressure of the grease within the valve body exertspressure on the valve ball and maintaining it in sealing contact withthe valve seat.
 16. The apparatus for the return of grease underpressure according to claim 15, wherein the valve seat comprises a bodyhaving an elongated internal passage of diameter smaller than that ofthe valve ball.
 17. The apparatus for the return of grease underpressure according to claim 16, wherein an activation rod is providedwhich comprises a stepped shaft, the smaller diameter end thereof beingslidably located within the internal passage of the valve seat.
 18. Theapparatus for the return of grease under pressure according to claim 17,wherein the larger diameter end of the activation rod is located in theproximity of a mechanical driver, which, upon activation, engages theactivation rod to advance the valve ball off the valve seat.
 19. Theapparatus for the return of grease under pressure according to claim 18,wherein the activation rod is loosely located within the valve seatpassage and is supported by a retaining formation which retains theactivation rod within the valve seat passage and maintains the rodsalignment with the mechanical driver.
 20. The apparatus for the returnof grease under pressure according to claim 17, in which the smallerdiameter end of the activation rod is dimensioned to permit grease tobypass the rod within the elongated passage and return to the greasereservoir.
 21. The apparatus for the return of grease under pressureaccording to claim 20, wherein the mechanical driver comprises aformation associated with a rotating lever / treadle, permittingengagement of the driver and the activation rod, which in turn opens therelief valve.
 22. The apparatus for the return of grease under pressureaccording to claim 14, wherein the one way flow control valve comprisesa valve ball and a valve seat, the pressure of the grease within thevalve body exerts pressure on the valve ball and maintaining it insealing contact with the valve seat.
 23. The apparatus for the return ofgrease under pressure according to claim 18, in which the smallerdiameter end of the activation rod is dimensioned to permit grease tobypass the rod within the elongated passage and return to the greasereservoir.
 24. The apparatus for the return of grease under pressureaccording to claim 19, in which the smaller diameter end of theactivation rod is dimensioned to permit grease to bypass the rod withinthe elongated passage and return to the grease reservoir.